Pass provisioned options via struct.

sdks/go/pkg/beam/core/runtime/harness/harness.go

@@ -45,25 +45,32 @@ import (
 // URNMonitoringInfoShortID is a URN indicating support for short monitoring info IDs.
 const URNMonitoringInfoShortID = "beam:protocol:monitoring_info_short_ids:v1"
 
-// TODO(herohde) 2/8/2017: for now, assume we stage a full binary (not a plugin).
+// Options for harness.Main that affect execution of the harness, such as runner capabilities.
+type Options struct {
+	RunnerCapabilities []string // URNs for what runners are able to understand over the FnAPI.
+	StatusEndpoint     string   // Endpoint for worker status reporting.
+}
 
-// Main is the main entrypoint for the Go harness. It runs at "runtime" -- not
+// MainWithOptions is the main entrypoint for the Go harness. It runs at "runtime" -- not
 // "pipeline-construction time" -- on each worker. It is a FnAPI client and
 // ultimately responsible for correctly executing user code.
+//
+// Deprecated: Prefer MainWithOptions instead.
 func Main(ctx context.Context, loggingEndpoint, controlEndpoint string) error {
+	return MainWithOptions(ctx, loggingEndpoint, controlEndpoint, Options{})
+}
+
+// MainWithOptions is the main entrypoint for the Go harness. It runs at "runtime" -- not
+// "pipeline-construction time" -- on each worker. It is a FnAPI client and
+// ultimately responsible for correctly executing user code.
+//
+// Options are optional configurations for interfacing with the runner or similar.
+func MainWithOptions(ctx context.Context, loggingEndpoint, controlEndpoint string, opts Options) error {
 	hooks.DeserializeHooksFromOptions(ctx)
 
-	// Extract environment variables. These are optional runner supported capabilities.
-	// Expected env variables:
-	// RUNNER_CAPABILITIES : list of runner supported capability urn.
-	// STATUS_ENDPOINT : Endpoint to connect to status server used for worker status reporting.
-	statusEndpoint := os.Getenv("STATUS_ENDPOINT")
-	runnerCapabilities := strings.Split(os.Getenv("RUNNER_CAPABILITIES"), " ")
 	rcMap := make(map[string]bool)
-	if len(runnerCapabilities) > 0 {
-		for _, capability := range runnerCapabilities {
-			rcMap[capability] = true
-		}
+	for _, capability := range opts.RunnerCapabilities {
+		rcMap[capability] = true
 	}
 
 	// Pass in the logging endpoint for use w/the default remote logging hook.
@@ -151,8 +158,8 @@ func Main(ctx context.Context, loggingEndpoint, controlEndpoint string) error {
 	}
 
 	// if the runner supports worker status api then expose SDK harness status
-	if statusEndpoint != "" {
-		statusHandler, err := newWorkerStatusHandler(ctx, statusEndpoint, ctrl.cache, func(statusInfo *strings.Builder) { ctrl.metStoreToString(statusInfo) })
+	if opts.StatusEndpoint != "" {
+		statusHandler, err := newWorkerStatusHandler(ctx, opts.StatusEndpoint, ctrl.cache, func(statusInfo *strings.Builder) { ctrl.metStoreToString(statusInfo) })
 		if err != nil {
 			log.Errorf(ctx, "error establishing connection to worker status API: %v", err)
 		} else {

sdks/go/pkg/beam/core/runtime/harness/init/init.go

@@ -22,6 +22,7 @@ import (
 	"context"
 	"encoding/json"
 	"flag"
+	"strings"
 	"time"
 
 	"fmt"
@@ -118,7 +119,18 @@ func hook() {
 	if err := syscallx.SetProcessMemoryCeiling(memLimit, memLimit); err != nil && err != syscallx.ErrUnsupported {
 		fmt.Println("Error Setting Rlimit ", err)
 	}
-	if err := harness.Main(ctx, *loggingEndpoint, *controlEndpoint); err != nil {
+
+	// Extract environment variables. These are optional runner supported capabilities.
+	// Expected env variables:
+	// RUNNER_CAPABILITIES : list of runner supported capability urn.
+	// STATUS_ENDPOINT : Endpoint to connect to status server used for worker status reporting.
+	statusEndpoint := os.Getenv("STATUS_ENDPOINT")
+	runnerCapabilities := strings.Split(os.Getenv("RUNNER_CAPABILITIES"), " ")
+	options := harness.Options{
+		StatusEndpoint:     statusEndpoint,
+		RunnerCapabilities: runnerCapabilities,
+	}
+	if err := harness.MainWithOptions(ctx, *loggingEndpoint, *controlEndpoint, options); err != nil {
 		fmt.Fprintf(os.Stderr, "Worker failed: %v\n", err)
 		switch ShutdownMode {
 		case Terminate:

sdks/go/pkg/beam/runners/universal/extworker/extworker.go

@@ -22,6 +22,7 @@ import (
 	"net"
 	"sync"
 
+	"github.com/apache/beam/sdks/v2/go/container/tools"
 	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/harness"
 	"github.com/apache/beam/sdks/v2/go/pkg/beam/log"
 	fnpb "github.com/apache/beam/sdks/v2/go/pkg/beam/model/fnexecution_v1"
@@ -89,10 +90,28 @@ func (s *Loopback) StartWorker(ctx context.Context, req *fnpb.StartWorkerRequest
 	ctx = grpcx.WriteWorkerID(s.root, req.GetWorkerId())
 	ctx, s.workers[req.GetWorkerId()] = context.WithCancel(ctx)
 
-	go harness.Main(ctx, req.GetLoggingEndpoint().GetUrl(), req.GetControlEndpoint().GetUrl())
+	opts := harnessOptions(ctx, req.GetProvisionEndpoint().GetUrl())
+
+	go harness.MainWithOptions(ctx, req.GetLoggingEndpoint().GetUrl(), req.GetControlEndpoint().GetUrl(), opts)
 	return &fnpb.StartWorkerResponse{}, nil
 }
 
+func harnessOptions(ctx context.Context, endpoint string) harness.Options {
+	var opts harness.Options
+	if endpoint == "" {
+		return opts
+	}
+	info, err := tools.ProvisionInfo(ctx, endpoint)
+	if err != nil {
+		log.Infof(ctx, "error talking to provision service worker, using defaults:%v", err)
+		return opts
+	}
+
+	opts.StatusEndpoint = info.GetStatusEndpoint().GetUrl()
+	opts.RunnerCapabilities = info.GetRunnerCapabilities()
+	return opts
+}
+
 // StopWorker terminates a worker harness, implementing BeamFnExternalWorkerPoolServer.StopWorker.
 func (s *Loopback) StopWorker(ctx context.Context, req *fnpb.StopWorkerRequest) (*fnpb.StopWorkerResponse, error) {
 	log.Infof(ctx, "stopping worker %v", req.GetWorkerId())